1. Technical Field of the Invention
The invention concerns a wafer baking oven in particular for flat wafers, low hollow wafers, sugar cones, wafer cups and wafer figures.
2. Description of the Prior Art
Different machine-made wafer or waffle products are known in the food and confectionery industries. These products are marketed in the filled or unfilled state and are generally known as confections. They may include, for example, wafer cones, wafer cups, wafer plates, flat wafer disks, low hollow wafers, wafer cookies, wafer rolls, ice cream cones, filled wafers, small filled wafer bars, wafer sections and the like. These wafer products are bakery items of a crisp, crunchy, brittle and fragile consistency.
The different individual wafer products may be prepared in different ways. In producing certain wafer products, the batter is baked in its final form to make products such as, for example, wafer cones, wafer cups, wafer disks, low hollow wafers, and the like.
In producing other wafer products, a wafer sheet of an endless wafer strip is first baked and then shaped into its final configuration while still in a soft baking state. The wafer product is then cooled and given its crisp, brittle consistency. Examples of this type of product are sugar cones, hollow wafers, sugar wafer rolls, and the like.
In the preparation of still further types of wafer products, several sheets of wafers are baked, cooled, covered with cream and stacked to form a block of wafers. This cream-filled wafer block or wafer sandwich is subsequently cut into small, handy pieces, packed into units of one or several pieces, possibly in an air tight manner, and distributed.
The various wafer products may be provided with coatings, depending on the product. This may include, for example, sugar or chocolate. It may also include different fillings such as, for example, ice cream, various creams, chocolates or the like.
A distinction should be made between these wafer or waffle products and the waffles usually baked in the home in waffle irons, representing a soft, roll or pancake-like baked product. These waffles produced in the home are not similar in any way in respect to their consistency and their applicability to the aforedescribed wafer products of the wafer industry.
Industrially produced wafers, baked already in their final form such as, for example, wafer cones, wafer cups, wafer figures, etc., and the individual wafers which are combined into wafer products after having been coated with a cream such as, for example, flat wafers, wafer sheets, low hollow wafers and the like, are produced in wafer baking ovens.
Wafer baking ovens are in most cases operated in a fully automatic manner, whereby liquid batter or dough is poured into wafer baking molds corresponding to the type of wafer desired. The molds pass through a baking chamber and the ready baked wafers are removed from the molds in the soft baking state following the passage of the baking period. The wafer baking molds are arranged in opening and closing baking tongs having upper and lower sections, one of which may be moved relative to the other, which tongs traverse the wafer oven by traveling from one end to the other and which are opened and closed in the front port preceding the wafer oven for the pouring of the batter or dough and removal of the individual wafers.
The wafer molds arranged in the baking tongs have different configurations in accordance with the type of wafer to be produced in the wafer mold. Thus, the wafer mold for the baking of wafer sheets or low hollow wafers consists of two baking sheets that are essentially flat with the exception of the pattern for the wafer sheets or the recesses for the low hollow wafers, in which case the sheets are equipped with lateral ledges to laterally close off the cavity existing when the wafer mold is closed. For other types of wafers, for example, for wafer or sugar cones, the baking mold consists of a two-part insert, one part being provided with recesses for the wafer cones and representing a female die, and the other part representing a male die entering the recesses of the female die in the closed state of the mold.
The parts of the wafer molds are arranged in the baking tongs so that, upon the opening of the baking tongs, the wafer molds also open for inserting the batter or removing the wafers. Thus, for example, in the case of a wafer baking mold comprising two wafer baking sheets, one of the baking sheets is arranged in the bottom part of the tong and the other in the top part of the tong. In a baking mold for wafer cones, the female die with its opening mechanism is arranged in the bottom part and the male die is arranged in the top part of the tongs. The opening of the baking tong is effected either by a mutual pivoting of the two parts of the tong around a common axis or by the lifting of one part of the tong from the other.
In the known wafer ovens or automatic wafer baking machines the individual baking tongs are lined up in a chain of tongs. The chain of tongs is arranged in the baking chamber and one end of the chain of tongs protrudes from one end of the chamber. In the area of the end of the chain of tongs protruding from the baking chamber, the batter charging station and the wafer discharge station are arranged. Together, the batter charging station and wafer discharge station form the front port of the wafer oven. The baking chamber of known wafer ovens is equipped at least over part of its length, with heating elements. The baking chamber is also surrounded by jacketing which, at least in part, is thermally insulated. This jacketing is equipped in part with doors, and the jacketing has a plurality of slots or orifices for the entry of combustion air to supply the heating elements arranged in the baking chamber. Combustion air enters the inside of the baking chamber primarily through the bottom area of the wafer oven which is open in the downward direction.
During the operation of the wafer baking oven, batter is placed in the open wafer molds in the front port, at the charging station, whereupon the molds are closed and transported in the closed state into the baking chamber. The batter in the molds is then baked during the passage of the mold through the baking chamber.
After the baking period, the closed wafer molds are transported from the baking chamber into the front port to the wafer discharge station. There, the baking tongs and the molds are opened, and the wafers are taken from the wafer oven. During the subsequent closing of the wafer molds at the charging station and during the baking process in the baking chamber, the water present in the batter evaporates as steam. This must be removed from the region of the front port and, together with the baking gases, from the baking chamber. In the known wafer ovens, this is effected in the region of the front port simply by opening a vapor exhaust. In this way, steam is removed from the baking chamber together with the baking gases and the combustion gases of the heating elements. In the process, in order to prevent the escape of the steam and the baking gases through the slots in the jacketing or through the downwardly open part of the baking chamber or through the end of the baking chamber open toward the front port, a volume of gas is exhausted which is substantially larger than is necessary for the removal of combustion and baking gases and of the steam. The volume of air required for this purpose is additionally suctioned in through the openings of the baking chamber and heated in the chamber or mixed with the hot atmosphere of the baking chamber, and then it is exhausted by way of the baking chamber exhausts. The volume of gas exhausted corresponds to 3 to 5 times the volume of the gases generated in, and to be exhausted from, the oven and the area of the front port.
In the known wafer baking ovens, an essential disadvantage resides in the fact that the additional volume of air exhausted with the baking gases, which consists essentially of steam and combustion gases and which is suctioned into the baking chamber, cools the wafer molds adjacent the inlet location. This air must itself be first heated to the temperature of the baking chamber. In order to prevent a harmful effect on the wafers in the molds from the cooling process of the molds, it is necessary to heat the baking molds, on the one hand, ard the atmosphere of the baking chamber, on the other hand, to a temperature higher than required for the baking process itself. A further disadvantage is that, for the heating of the additional volume of air, a high heating capacity must be provided in the baking chamber. Furthermore, for exhausting the steam, the baking gases, the combustion gases and the additional volume of air, the blower installed in the exhaust of the baking oven must be of high capacity.